The Museum of Avilés Urban History is a compact orientation point for the old town. Its exhibits follow the city from medieval charter and port life through industrial expansion, using the estuary as the thread that explains why Avilés grew where and how it did.
Visit early in your walk rather than at the end. The museum helps make sense of the arcaded streets, churches, port edges, and the leap from old mercantile town to modern cultural projects such as the Niemeyer Centre.